Associations of blood pressure with all-cause and cause-specific mortality within different multimorbidity patterns among patients with type 2 diabetes

Abstract Funding Acknowledgements Type of funding sources: None. Background Achieving blood pressure targets is a key component of type 2 diabetes (T2D) management and is considered important in reducing mortality risk. However, little is known about whether different multimorbidity patterns would modify the associations between blood pressure and mortality among patients with T2D. Method In the prospective population-based UK Biobank cohort, prevalent T2D was defined as fasting blood glucose ≥7.0 mmol/L (126 mg/dL), non-fasting blood glucose ≥11.1 mmol/L (200 mg/dL), HbA1c level ≥47.5 mmol/mol (6.5%), self-reported physician-diagnosed diabetes, current use of blood glucose-lowering medication, or having hospital inpatient records occurring before the baseline study assessment. We qualitatively assessed multimorbidity (defined as the presence of the 39 self-reported long-term health conditions [in addition to T2D]) in three ways: total, concordant, and discordant condition, and calculated disease counts for each multimorbidity type. Cox regression models were used to estimate the associations of blood pressure and all-cause/cause-specific mortality within different multimorbidity patterns. Results 24,647 participants with prevalent T2D at baseline were included (mean age 59.8 years, 36.9% women). During a median follow-up time of 11.8 years (interquartile range: 11.0-12.6), 4114 (16.7%) individuals died, of whom 1189 (4.8%) died of cardiovascular disease. A U-shaped association was found between systolic blood pressure (SBP) and risk of mortality among T2D patients across total, concordant, and discordant multimorbidity patterns, and the related effect estimations increased with accumulating multimorbidity counts; whereas a reverse J-shaped association was indicated for diastolic blood pressure (DBP) in specific multimorbidity patterns. Notably, the lowest risk of death was consistently observed around 130~140 mmHg for SBP and 80~90 mmHg for DBP within different multimorbidity patterns. Among participants with none, one, two, and more than two total multimorbidity counts, respectively, those having SBP <120 mmHg, compared to having SBP around 130~139 mmHg, had a higher risk of all-cause mortality with a hazard ratio (HR) 1.08 (95 %CI: 0.81, 1.43), 1.36 (1.11, 1.67), 1.33 (1.04, 1.69), and 1.43 (1.09, 1.87), respectively; and those with DBP <70 mmHg, compared to having DBP 80~89 mmHg, had an HR (95%CI) of 1.21 (0.99, 1.48), 1.52 (1.30, 1.79), 1.35 (1.10, 1.65), and 1.34 (1.08, 1.67) for all-cause mortality, and 1.75 (1.20, 2.56), 2.03 (1.52, 2.70), 1.41 (1.00, 1.99), and 1.71 (1.17, 2.50) for cardiovascular mortality. Conclusion Low and high SBP and low DBP were related to a higher risk of all-cause and cardiovascular mortality in individuals with T2D, regardless of their multimorbidity patterns. This implies that different multimorbidity counts or types should not affect optimal blood pressure target in diabetes management.